CN102821530A - Driving device for cold cathode tube and related driving method - Google Patents
Driving device for cold cathode tube and related driving method Download PDFInfo
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- CN102821530A CN102821530A CN2011102382740A CN201110238274A CN102821530A CN 102821530 A CN102821530 A CN 102821530A CN 2011102382740 A CN2011102382740 A CN 2011102382740A CN 201110238274 A CN201110238274 A CN 201110238274A CN 102821530 A CN102821530 A CN 102821530A
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- 238000000034 method Methods 0.000 title claims description 22
- 238000001514 detection method Methods 0.000 abstract 3
- 238000006243 chemical reaction Methods 0.000 description 4
- 238000010586 diagram Methods 0.000 description 4
- 238000010438 heat treatment Methods 0.000 description 3
- QSHDDOUJBYECFT-UHFFFAOYSA-N mercury Chemical compound [Hg] QSHDDOUJBYECFT-UHFFFAOYSA-N 0.000 description 2
- 229910052753 mercury Inorganic materials 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000003990 capacitor Substances 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000010304 firing Methods 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 239000011261 inert gas Substances 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 238000004904 shortening Methods 0.000 description 1
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Classifications
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- H—ELECTRICITY
- H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
- H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- H05B41/00—Circuit arrangements or apparatus for igniting or operating discharge lamps
- H05B41/14—Circuit arrangements
- H05B41/26—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc
- H05B41/28—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc using static converters
- H05B41/282—Circuit arrangements in which the lamp is fed by power derived from dc by means of a converter, e.g. by high-voltage dc using static converters with semiconductor devices
- H05B41/285—Arrangements for protecting lamps or circuits against abnormal operating conditions
- H05B41/2858—Arrangements for protecting lamps or circuits against abnormal operating conditions for protecting the lamp against abnormal operating conditions
Abstract
A driving device for a cold cathode tube comprises a driving circuit, a detecting element and a control circuit. The driving circuit is used for driving the cold cathode tube. The detecting element is used for detecting the driving characteristic of the cold cathode tube as a detection output. The control circuit is coupled to the detection element and the driving circuit and used for controlling the driving circuit according to the detection output.
Description
Technical field
(cold cathode fluorescent lamp, drive unit CCFL) and method especially relate to drive unit and method that a kind of detecting result according to cold-cathode tube adjusts drive current to the present invention relates to a kind of cold-cathode tube.
Background technology
Cold-cathode tube (cold cathode fluorescent lamp; CCFL) be a kind of of fluorescent tube, general cold-cathode tube scribbles one deck fluorophor at tube inner wall, and at the inner mercury of enclosing small amounts of inert gas and trace of fluorescent tube; After the voltage pressurization; The mercury electronics can impact with gas atom each other, and produces ultraviolet ray, after the fluorophor of tube wall changes, then converts visible light into.Because cold-cathode tube has long service life, volume is little, power is low, high brightness, high lumen, characteristic such as energy-efficient, hereat often is applied in the normal lighting.
Yet general cold-cathode tube receives temperature to be influenced greatly, under low temperature environment; Lighting tube brightness can significantly decrease; And the needed starting resistor of fluorescent tube can significantly rise, and the oneself of fluorescent tube heating (self heating) characteristic also can directly the brightness after startup causes great influence to fluorescent tube, for instance; Because the firing rate of cold-cathode tube is slower, the time of heating certainly will need to prolong to reach desirable lighting tube brightness smoothly.
Summary of the invention
Because above-mentioned problem the invention provides a kind of drive unit and driving method that is used for cold-cathode tube, in the hope of solving the above problems.
A kind of embodiment of the present invention has disclosed a kind of drive unit that is used for cold-cathode tube, and this drive unit includes drive circuit, detecing element and control circuit.This drive circuit is in order to drive this cold-cathode tube.This detecing element is used as detecting output in order to the drive characteristic of detecting this cold-cathode tube.This control circuit is coupled to this detecing element and this drive circuit, in order to control this drive circuit according to this detecting output.
According to the drive unit of this embodiment, wherein when this detecting output presented first numerical value, this this drive circuit of control circuit control was set this cold-cathode tube and is had first drive current; And when this detecting output presented the second value that is different from this first numerical value, this this drive circuit of control circuit control was set this cold-cathode tube and is had second drive current that is different from this first drive current.
According to the drive unit of this embodiment, wherein the drive current of this this cold-cathode tube of detecing element detecting produces this detecting output.
Preferably, according to the drive unit of this embodiment, wherein this control circuit includes: (overdrive) reference circuit of overdriving, in order to produce reference voltage; And feedback control circuit, be coupled to this reference circuit of overdriving, in order to produce the driving signal, adjust this drive current of this cold-cathode tube to control this drive circuit according to this detecting output and this reference voltage.
Preferably, in this drive unit, this reference circuit of overdriving produces first reference voltage at very first time point, and produces second reference voltage that is different from this first reference voltage at second time point that is different from this very first time point.
Preferably, in this drive unit, when this drive characteristic that this detecing element detected is higher than a fault value, this feedback control circuit restriction this driving signal in a preset range to prevent that this drive current is above an electric current fault value.
Another kind of embodiment of the present invention has disclosed a kind of driving method that is used for cold-cathode tube, and this driving method includes: the drive characteristic of detecting this cold-cathode tube is used as detecting output; And control this cold-cathode tube according to this detecting output.
According to the driving method of this embodiment, wherein when this detecting output presents first numerical value, control this drive circuit and set this cold-cathode tube and have first drive current; When this detecting output presents the second value that is different from this first numerical value, control this drive circuit and set this cold-cathode tube and have second drive current that is different from this first drive current.
According to the driving method of this embodiment, wherein should detect the drive current of exporting according to this cold-cathode tube and produce.
Preferably, in the method, the method that drives this cold-cathode tube according to this detecting output includes: produce reference voltage; And produce the driving signal according to this detecting output and this reference voltage, to adjust this drive current of this cold-cathode tube.
Preferably, in the method, the step that produces this reference voltage includes: produce first reference voltage at very first time point, and produce second reference voltage that is different from this first reference voltage at second time point that is different from this very first time point.
Preferably, in the method, when this drive characteristic is higher than a fault value, limit this driving signal in a preset range to prevent that this drive current from surpassing an electric current fault value.
Description of drawings
Fig. 1 be according in the embodiments of the invention in order to the illustrative diagram of the drive unit that drives cold-cathode tube.
Fig. 2 is the illustrative diagram of control circuit in one embodiment of the invention.
Fig. 3 be according in the embodiments of the invention in order to the structural representation of the drive unit that drives cold-cathode tube.
Embodiment
In the middle of specification and claims, used some vocabulary to censure specific element.One of ordinary skill in the art should understand, and hardware manufacturer may be called same element with different nouns.This specification and claims are not used as distinguishing the mode of element with the difference of title, but the criterion that is used as distinguishing with the difference of element on function.Be an open term mentioned " comprising " in the middle of specification and claims in the whole text, so should be construed to " comprise but be not limited to ".In addition, " couple " speech and comprise any indirect means that are electrically connected that directly reach at this.Therefore, be coupled to second device, then represent this first device can directly be electrically connected in this second device, or be electrically connected to this second device through other device or the intersegmental ground connection of connection hand if describe first device in the literary composition.
Please with reference to Fig. 1, its be according in the embodiments of the invention in order to the illustrative diagram of the drive unit 1200 that drives cold-cathode tube 1100.Drive unit 1200 includes drive circuit 1210, detecing element 1220 and control circuit 1230.Drive circuit 1210 is in order to drive cold-cathode tube 1100.1220 drive characteristic SF in order to detecting cold-cathode tube 1100 of detecing element are used as detecting output SD; In this embodiment; Drive characteristic SF is set to the electric current in cold-cathode tube 1100 fluorescent tubes, that is the drive current of detecing element 1220 meeting detecting cold-cathode tubes 1100 produces detecting output SD.1230 of control circuits can come control Driver Circuit 1210 according to detecting output SD; This drive current with adjustment cold-cathode tube 1100; When detecting output SD presented first numerical value, control circuit 1230 control Driver Circuit 1210 were set cold-cathode tube 1100 and are had first drive current; And when detecting output SD presented the second value that is different from this first numerical value, control circuit 1230 control Driver Circuit 1210 were set cold-cathode tube 1100 and are had second drive current that is different from this first drive current.Yet; The foregoing description is merely the preferred embodiments of the present invention, is not to be used for limiting scope of the present invention, for instance; The temperature that detecing element 1220 also can be detected cold-cathode tube 1100 is used as detecting output SD; Cross when low when temperature, control circuit just control Driver Circuit 1210 is adjusted cold-cathode tube 1100, and this drive current is improved to add toggle speed and the brightness that improves cold-cathode tube 1100.
Please come further to understand the operation of control circuit 1230 with reference to Fig. 2, Fig. 2 is the illustrative diagram of control circuit 1230 in one embodiment of the invention.Control circuit 1230 includes overdrive (overdrive) reference circuit 1231 and feedback control circuit 1232.The reference circuit 1231 of overdriving is given feedback control circuit 1232 at this in order to produce reference voltage Vref; And feedback control circuit 1232 is adjusted this drive current of cold-cathode tube 1100 in order to produce driving signal Sdrv according to detecting output SD and reference voltage Vref with control Driver Circuit 1210.The reference circuit 1231 of wherein overdriving produces first reference voltage at very first time point, and produces second reference voltage that is different from this first reference voltage at second time point that is different from this very first time point.
Please understand thin portion (in detail) operation of drive unit 1200 with reference to Fig. 3, Fig. 3 for according in the embodiments of the invention in order to the structural representation of the drive unit 1200 that drives a cold-cathode tube 1100.In the embodiments of figure 3, the reference circuit 1231 of overdriving includes diode D1, capacitor C 1 and resistance R 1, R2 and R3, and receives service voltage Vcc.1220 of circuit for detecting have resistance R _ f b and diode Dfb1, Dfb2.Feedback control circuit 1232 then includes operational amplifier (OP amplifier) OP1 and conversion element 1232A.Operational amplifier OP1 can compare two voltages of input, that is Vref and Vfb, and the result after will comparing again sends conversion element 1232A to, converts controlling signal into by conversion element 1232A and gives drive circuit 1210.1220 of circuit for detecting can convert this drive current in the cold-cathode tube 1100 into voltage signal, therefore can draw:
I＝Vfb/Rfb (1)
Wherein I is this drive current.
Note that because the circuit of operational amplifier OP1 mechanism, voltage Vfb can be adjusted to and be equal to voltage Vref, and because the circuit characteristic of the reference circuit 1231 of overdriving itself, the reference circuit 1231 of overdriving can draw when just being started:
Vref＝(Vcc×R3)/(R1+R3) (2)
Therefore, when just starting, this drive current in the cold-cathode tube 1100 can be represented as follows:
I＝[(Vcc×R3)/(R1+R3)]/Rfb (3)
And starting after T after a while, because the circuit characteristic of the reference circuit 1231 of overdriving itself can draw following formula:
Vref＝(Vcc×R3)/(R1+R2+R3) (4)
T＝5[(R1+R3)//R2]×C1 (5)
Therefore, afterwards, this drive current in the cold-cathode tube 1100 can be represented as follows through T after a while (that is, needed start-up time) starting:
I＝[(Vcc×R3)/(R1+R3+R3)]/Rfb (6)
Can know by above-listed mathematical expression; This drive current in the cold-cathode tube 1100 is when just starting; Can have higher current value, be beneficial to quicken the startup of cold-cathode tube 1100, and start a period of time later; It is stable that this drive current in the cold-cathode tube 1100 just can reduce and keep, in order to avoid cause cold-cathode tube shortening in 1100 useful lifes or damage.Note that for fear of excessive drive current that through cold-cathode tube 1100 and cause damage the present invention provides a mechanism to prevent to drive signal Sdrv to promote the drive current of cold-cathode tube 1100 too high in addition.When the drive characteristic SD that is detected when detecing element 1220 was higher than a fault value, feedback control circuit 1232 just can limit and drive signal SD in a preset range, surpasses an electric current fault value and cold-cathode tube 1100 is damaged to prevent this drive current.
In sum; The invention provides a kind of drive unit and drive method thereof that is used for cold-cathode tube; Via the drive characteristic of detecting cold-cathode tube, the drive current that drive unit of the present invention can be adjusted this cold-cathode tube quickens toggle speed or promotes brightness.In addition, the present invention provides a kind of protection mechanism excessive and this cold-cathode tube is damaged with the electric current of avoiding overdriving in addition.
The above is merely the preferred embodiments of the present invention, and all equivalent variations that claim is done according to the present invention and modification all should belong to covering scope of the present invention.
The main element symbol description
1100 pipes, 1200 drive units
1210 drive circuits, 1220 detecing elements
1230 control circuits 1231 reference circuit of overdriving
1232 feedback control circuit 1232A conversion elements
SF drive characteristic SD detects output
Sdrv drives signal Vcc service voltage
Vref, Vfb reference voltage D1, Dfb1, Dfb2 diode
C1 electric capacity R1, R2, R3, Rfb resistance
The OP1 operational amplifier.
Claims (12)
1. drive unit that is used for cold-cathode tube includes:
Drive circuit is in order to drive said cold-cathode tube;
Detecing element is used as detecting output in order to the drive characteristic of detecting said cold-cathode tube; And
Control circuit is coupled to said detecing element and said drive circuit, controls said drive circuit in order to export according to said detecting.
2. drive unit according to claim 1, wherein when said detecting output presents first numerical value, said control circuit is controlled said drive circuit and is set said cold-cathode tube and have first drive current; And when said detecting output presented the second value that is different from said first numerical value, said control circuit was controlled said drive circuit and is set said cold-cathode tube and have second drive current that is different from said first drive current.
3. the drive current that drive unit according to claim 1, wherein said detecing element are detected said cold-cathode tube produces said detecting output.
4. drive unit according to claim 3, wherein said control circuit includes:
The reference circuit of overdriving is in order to produce reference voltage; And
Feedback control circuit is coupled to the said reference circuit of overdriving, and in order to produce the driving signal according to said detecting output and said reference voltage, adjusts the said drive current of said cold-cathode tube to control said drive circuit.
5. drive unit according to claim 4, the wherein said reference circuit of overdriving produces first reference voltage at very first time point, and produces second reference voltage that is different from said first reference voltage at second time point that is different from said very first time point.
6. drive unit according to claim 4; Wherein when said drive characteristic that said detecing element detected is higher than a fault value, said feedback control circuit limit said driving signal in a preset range to prevent that said drive current from surpassing an electric current fault value.
7. driving method that is used for cold-cathode tube, said driving method includes:
The drive characteristic of detecting said cold-cathode tube is used as detecting output; And
Export according to said detecting and to control said cold-cathode tube.
8. driving method according to claim 7 wherein when said detecting output presents first numerical value, is controlled said drive circuit and is set said cold-cathode tube and have first drive current; When said detecting output presents the second value that is different from said first numerical value, control said drive circuit and set said cold-cathode tube and have second drive current that is different from said first drive current.
9. driving method according to claim 7, wherein said detecting output produces according to the drive current of said cold-cathode tube.
10. driving method according to claim 9, wherein export the method that drives said cold-cathode tube and include according to said detecting:
Produce reference voltage; And
Produce the driving signal according to said detecting output and said reference voltage, to adjust the said drive current of said cold-cathode tube.
11. driving method according to claim 10, the step that wherein produces said reference voltage includes:
Produce first reference voltage at very first time point, and produce second reference voltage that is different from said first reference voltage at second time point that is different from said very first time point.
12. driving method according to claim 10, wherein when said drive characteristic is higher than a fault value, limit said driving signal in a preset range to prevent that said drive current from surpassing an electric current fault value.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| TW100120391 | 2011-06-10 | ||
| TW100120391A TW201251511A (en) | 2011-06-10 | 2011-06-10 | Driving apparatus for cold cathode fluorescent lamp and related driving method |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN102821530A true CN102821530A (en) | 2012-12-12 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2011102382740A Pending CN102821530A (en) | 2011-06-10 | 2011-08-18 | Driving device for cold cathode tube and related driving method |
Country Status (3)
| Country | Link |
|---|---|
| US (1) | US20120313550A1 (en) |
| CN (1) | CN102821530A (en) |
| TW (1) | TW201251511A (en) |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1808875A (en) * | 2005-01-19 | 2006-07-26 | 美国芯源系统股份有限公司 | Method and apparatus for DC to AC power conversion for driving discharge lamps |
| CN201349353Y (en) * | 2009-01-19 | 2009-11-18 | 冠捷投资有限公司 | Double-dimming backlight source drive device |
| US20090284163A1 (en) * | 2008-05-15 | 2009-11-19 | Naixing Kuang | Method and apparatus for driving multiple parallel discharge lamps |
| CN101657059A (en) * | 2008-08-18 | 2010-02-24 | 凹凸电子（武汉）有限公司 | Inverter controller and driving circuit |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101662874B (en) * | 2008-09-19 | 2013-06-05 | 成都芯源系统有限公司 | Driving circuit and driving method for discharge lamp |
-
2011
- 2011-06-10 TW TW100120391A patent/TW201251511A/en unknown
- 2011-08-18 CN CN2011102382740A patent/CN102821530A/en active Pending
-
2012
- 2012-04-09 US US13/442,822 patent/US20120313550A1/en not_active Abandoned
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1808875A (en) * | 2005-01-19 | 2006-07-26 | 美国芯源系统股份有限公司 | Method and apparatus for DC to AC power conversion for driving discharge lamps |
| US20090284163A1 (en) * | 2008-05-15 | 2009-11-19 | Naixing Kuang | Method and apparatus for driving multiple parallel discharge lamps |
| CN101657059A (en) * | 2008-08-18 | 2010-02-24 | 凹凸电子（武汉）有限公司 | Inverter controller and driving circuit |
| CN201349353Y (en) * | 2009-01-19 | 2009-11-18 | 冠捷投资有限公司 | Double-dimming backlight source drive device |
Also Published As
| Publication number | Publication date |
|---|---|
| US20120313550A1 (en) | 2012-12-13 |
| TW201251511A (en) | 2012-12-16 |
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Application publication date: 20121212 |